Patients are followed in this study to determine the nature and extent of auditory system deficits in this group of boney disorders. Originally developed in conjuction with Dr. Jay Shapiro and his study of metabolic bone disorders, the audiologic research continues to 1) assess new patients and 2) monitor previously studied patients over time re progressive hearing loss. Middle ear function continues to be studied with otoadmittance measurements to attempt to understand the auditory deficits to frequently accompanying OI. Further, first degree family members are also studied audiologically in an effort to find sensitive indices of auditory function related to carrier status and/or subclinical disease. Several publications and presentations have accrued from this work, but none in this fiscal year.